Why it matters: As communications become more closed off and private, experts worry that private group forums online may be festering hateful activity that could manifest itself in dangerous offline behavior.

Driving the news: Facebook said Wednesday that it would be simplifying its groups policy to make groups on its platform either "public" or "private" so that it's easier for group members to understand who can and cannot see their posts.

The setting update essentially makes it easier for group owners to see whether or not their posts are publicly accessible.

Last month, ProPublica reported that border patrol agents were joking about migrant deaths and posting sexist memes in a private Facebook group that had nearly 10,000 members. ProPublica was leaked the contents from the group page, which had been active for years.

Facebook says it has heard from users that they wanted more control over how their groups can be discovered.

Between the lines: Facebook isn't the only platform to struggle with closed-off groups that spew hateful rhetoric.

Reddit “quarantined” one of its biggest pro-Trump groups in June over violent threats being posted by group members. Quarantining groups means that the groups can remain on the platform, but they can't earn revenue and visitors to the groups have to opt-in to viewing the content after receiving a warning message about it.

8chan, the anonymous message board that often hosts conspiracy theories and hate speech, is under pressure from lawmakers, activists and even its own creator to crack down on forums that serve as a breeding ground for hate speech. On Wednesday, the House Homeland Security Committee issued a bipartisan subpoena to 8chan's owner, Jim Watkins, to understand what's being done to counter extremism on the platform.

Be smart: Facebook, Reddit and other forums are reluctant to ban or take down specific groups because they don't want to infringe on free speech rights. Instead, most take steps to demote groups, making them hard to find, or to remove incentives for posting incendiary content.

The bottom line: Monitoring hate speech, even on mainstream social sites, is proving to be difficult in a world that's growing increasingly privacy-centric.